The clear superiority of imipramine to placebo or other drugs in the treatment of childhood enuresis has been demonstrated. However, 30-50% of treated children do not respond at all, and the relapse rate is often high among responders. The mechanism of action of the drug and factors responsible for the uneven success, are at present, unknown. This study seeks to determine 1) if variation in response to imipramine treatment is due to variations in serum levels obtained of the drug or its metabolites; 2) how improvement in psyhological functioning relates to reduction in enuretic frequency and drug levels; and 3) if important side effects vary directly with the serum level of imipramine or one of its metabolites. Twenty enuretic children aged 7-14 hospitalized on a psychosomatic unit will be studied during a baseline phase, a placebo phase and an imipramine treatment phase. Quantity and frequency of nocturnal enuretic episodes will be monitored remotely with a sensitive impedence bridge apparatus. Serum levels of imipramine and its three active metabolites will be measured at the end of each week of treatment. A daily behavioral index will quantify changes in psychological functioning during the hospitalization. Data on imipramine side effects will also be collected. The results should allow the clinician to more effectively prescribe imipramine for enuretic children and shed light on the drug's mechanism of action.